Water for poultry

Most of the standards that
we are attempting to apply to animal drinking water are taken from those set
for humans, and even they have a rather short history. The Public Health
Service Act of 1962 was some of the first human water quality legislation and
dealt only with sanitary surveys of water involved in interstate commerce. It
was the Safe Drinking Water Act of 1974 that made the Environmental Protection
Agency responsible for establishing national drinking water regulations,
overseeing the safety of public water systems and protecting underground water
sources against contamination.

Problems with Measurement Standards for Poultry-Quality
Water

Some of the measurement
characteristics commonly used to define human potable water quality, such as
pH, hardness and electrical conductivity, are not very useful in predicting
poultry performance. Hydrogen ion concentration (pH) tells nothing about the
solution's buffering capacity or the identity and amount of individual ions.
Hardness indicates the tendency to precipitate soap or to form scale on heated
surfaces. What one really needs to know is the individual concentrations of calcium
and/or magnesium, the principal contributors to this measurement. Electrical
conductivity provides a measure of total mineral load and no individual ion
analysis.

A number of popular articles
have been written about water quality for poultry, yet very few research papers
dealing with the subject could be found in the scientific journals during the
past ten years. Clearly, we have much work ahead to develop an accurate
specialized tolerance profile for poultry. The first step towards this goal was
made by a National Academy of Sciences subcommittee in 1974 with their review
booklet entitled “Nutrients and Toxic Substances in Water for Livestock and
Poultry.” That publication summarized the literature before 1974 and indicated
that a total soluble salt level of 1000 ppm or less would present no problem to
livestock or poultry. It also provides recommended limits for several other
potentially toxic substances (As, Cd, Cr, Co, Cu, F, Pb, Hg, Ni, N02, N03, V
and Zn). Many of these are heavy metals and would not be a problem except in
special situations. Several of the popular articles carry compilations of
“good, maximum, tolerable or threshold” values for poultry water supplies. Most
of these hinge on human standards, the NRC publication or a combination of other
tables and are, overall, quite variable. For instance, iron tolerances ranged
from 0 to 50 ppm, nitrates from 20 to 200 ppm, sulfates from 200 to 1000 ppm
and sodium from 50 to 1000 ppm. Some of this variation is due to the standard
pitfall of trying to consider each element individually when there are many
interactions that influence their tolerance, but a paucity of research data is
the biggest culprit.